One of the varieties is the same as the apolescent Labradorite rock of Labrador.
"The Student's Elements of Geology"
Sir Charles Lyell
9.44 0.37 1.10 5.03 W 0.71 2.72. Labradorite.
"The Student's Elements of Geology"
Sir Charles Lyell
It would be just as sensible to say that Labradorite, which is rare, should be as costly as diamonds.
"The Story of the Trapper"
A. C. Laut